Obesity is one of the major chronic diseases threatening people′s health, which is mainly caused by the expansion of adipose tissue. In the human body, adipose tissue is a dynamic endocrine organ responsible for energy homeostasis. Obesity is associated with metabolic disorders, altered steroid secretion, chronic subclinical inflammation, and an increased risk of many cancers. Tumor cells are closely related to adipocytes in microenvironment, on the one hand, adipocyte⁃derived cytokines, such as IL⁃6, CCL2, TNF-α, leptin and adiponectin, can promote tumor invasion and metastasis through activation of different signaling pathways. Free fatty acids and lipid droplets derived from adipocytes can be transferred to tumor cells through FABP4, CD36 and other transporters, which can increase the rate of tumor β oxidation, produce a lot of ATP, and promote the division and proliferation of tumor cells. On the other hand, adipocytes can induce metabolic reprogramming of Treg cells, CD8+ cytotoxic T cells and macrophages, promote the proliferation of Treg cells and M2⁃type macrophages, inhibit the tumor⁃killing activity of CD8+ cytotoxic T cells, and lead to tumor immune escape. The reprogramming of neutrophils disrupts the adhesion of vascular endothelial cells and leads to increased vascular wall permeability, which is conducive to the passage of tumor cells through the vascular wall and metastasis to distant places. This review mainly explores the relationship between adipocytes and tumor metastasis, aiming to provide new targets for tumor therapy.